Device for stacking bags

ABSTRACT

A bag stacking device to be located downstream of a bag welding machine wherein a bag support member is positioned to receive a stack of bags being built up and pinching fingers are positioned to rest on the lateral edges of the bag of the stack.

United States Patent [191 Lagain Feb-25,1975

[ DEVICE FOR STACKING BAGS [76] Inventor: Georges Lagain, 14, rue de Seine,

95 Argenteuil, France [22] Filed: July 18, 1973 211 App]. No.: 380,340

[30] Foreign Application Priority Data July 28, 1972 France 72.27437 [52] U.S. Cl 156/510, 83/86, 93/33 H, 156/515, 156/563,156/583, 214/6 F [51] Int. Cl B32b 31/00, B30b 15/34 [58] Field of Search 156/583, 564, 558, 566, 156/559, 569, 563, 228, 530, 251, 536, 515, 563; 93/33 H, 33 R, 93 HT; 83/86, 96, 92, 84, 94, 29; 270/82, 85; 271/220; 214/6 F; 219/243 [56] References Cited UNITED STATES PATENTS 1,874,816 8/1932 Shipley 83/86 12/1960 Harrison et al......... 219/243 3,157,553 11/1964 Spallina 219/243 3,255,653 6/1966 Greuttner et al. 83/96 3,384,528 5/1968 Lehmacher et a1 93/33 H 3,457,814 7/1969 Muchnick 83/86 3,580,142 5/1971 Stock et al 93/33 H 3,587,410 6/1971 Dechanciaux... 156/583 3,713,954 1/1973 Clark et al. 156/548 3,810,420 5/1974 Ravel 156/583 Primary ExaminerCharles E. Van Horn Assistant ExaminerJ. Gallagner Attorney, Agent, or FirmBrooks Haidt & Haffner [57] ABSTRACT A bag stacking device to be located downstream of a bag welding machine wherein a bag support member is positioned to receive a stack of bags being built up and pinching fingers are positioned to rest on the lateral edges of the bag of the stack.

6 Claims, 7 Drawing Figures PMEN TH? MB 2 5 i975 SHEET 3 BF 3 DEVICE FOR STACKING BAGS The present invention relates to a device for stacking bags. In order to fabricate bags from a plastic tubing or film, it is known to use machines in which the tubing or film, carried along with a translational movement, is cut off and welded at definite intervals. The bags are then stacked at the outlet of this machine in order to make it possible for the operator easily to recover a large pile of bags.

French Pat. No. 1,594,567 discloses a bag stacking device in which the pile of bags is pinched at one of its ends, between an edge of the lower-weldingjaw extending downstream from the jaw along the direction of movement of the tubing, and a supporting component. A holding component cooperates withthe supporting component in order to grip the bags when the supporting component moves away from the edge of the jaw, for stacking a new bag.

Now this device, in which one of the ends of the bags is held pinched, is entirely satisfactory in the case of bags having only a single welded side, but it is more difficult to use it on bags having welds at both ends, because of the sticking of the welds of adjacent stacked bags. It is an object of the invention to overcome this disadvantage by using means which make it possible to pinch the bags by their side edges.

According to the invention, there is provided a device for forming a stack of bags from a film or tubing, comprising at least two welding jaws at least one of which is mobile and carries means for cutting the tubing or film, characterised in that a supporting member is positioned downstream from the jaws and has a face for supporting the stacked bags, and in that at least one pair of pinching fingers is positioned to rest on the two side edges of the stacked bags to hold the bags on said supporting member.

Other objects and advantages of the invention will be better understood on reading the following description of one embodiment, referring to the attached drawing in which:

FIG. 1 is a view in front elevation of the device for stacking bags mounted at the outlet of a machine for fabricating bags;

FIG. 2 is a view in longitudinal cross-section of the machine for fabricating bags and of the stacking device showing the main components;

FIG. 3 is a detail view, in front elevation, of the device;

FIG. 4 is a cross-sectional view along the line IV-IV of FIG. 3;

FIG. 5 is a schematic view showing the first stage of holding a bag which hasjust been deposited on the pile;

FIG. 6 is the same view as in FIG. 3, showing the raising of the pinching fingers; and

FIG. 7 is the same view as in FIG. 3, showing the bag inserted on the pile under the pinching fingers.

A machine for fabricating bags, which comprises especially a pair of rotating pinch rollers l and 1a advancing a plastic tubing 2 along the direction F in which it is unwound in the machine has been partially represented in FIGS. 1 and 2. Behind the rollers 1 and la, are two lower welding jaws 3 and 4 which are fixed and co-operate with two upper welding jaws 3a and 4a which can move in a vertical plane. A cutting component 5 is located between the upper weldingjaws 3a and 4a.

The jaws 3a and 4a and the cutting component 5 are mounted on a transverse beam 6 which is firmly fixed at its two ends to vertically extending rods 7'and 7a which are slidably mounted in bearings 8' and 8a firmly fixed to the frame 9 of the machine. At their ends, the rods 7 and 7a are equipped with wheels 10 and 10a which roll on earns 11 and 11a keyed to a shaft l2'rotated by a drive means (not shown).

Springs 13 and 13a fixed to the beam 6 and to the frame 9 of the machine ensure that the cam follower wheels 10 and 10a are kept in contact with the cams II and 11a.

As'the cams 11, 11a allow the transverse beam 6 to descend in the direction of the arrow A, the jaws 3a and 4a contact the tubing 2 to make the welds of the bottom of a bagv being manufactured and of the top of a completed bag 14 removed at the outlet of the machine. Thereafter, the cutting component 5 severs the bag 14 from the tubing 2 and the end 140 of the bag 14 is released from the jaws 4-and 4a during rising of the beam 6, under the action of a jet 15 of compressed air (FIG. 4) coming from a manifold 16 equipped with orifices and extending over the entire width of the machine.

Although the machine illustrated has two pairs of welding jaws, it is-quite obvious that it would be possible to use a single pair of jaws, 3 and 3a, for bags welded at one endonly.

The device for stacking the bags according to the invention is located downstream from the jaws 4 and 4a and comprises a supporting component 17 which consists of a bar fixed at the top end of at least one threaded rod 18 (FIG. I) screwed into a rod 19 slidably mounted in a cross-bar 20 fixed to the frame 9.

A ring 21 is screwed onto the threaded rod 18 and forms an abutment for the top end of a helical compression spring 22 the other end of which abuts the crossbar 20 so as to urge the supporting component 17 upwardly against at least one pair of pinching fingers 23 and 23a firmly fixed to sleeves 24 fitted on a transverse bar 25. Each sleeve 24 carrying a finger can be moved along the bar 25 transversely to the direction of tubing advance and fixed along the width of the bags by means of the locking screw 26.

The bar 25 is firmly fixed at its two ends to two vertical rods 26 and 26a mounted for longitudinal sliding movement.

At their lower ends, the rods 26 and 26a each carry a cam follower wheel 27 and 27a engaging a respective rotating cam 28 or 28a under the action of springs 29 and 29a fixed between the bar 25 and the frame 9, the said earns 28 and 28a being keyed onto the same rotating shaft 12 as are the earns 11, 11a. This arrangement makes it possible to hold the pile of bags 30 between the upper surface 17a of the supporting component 17 and the fingers 23 and 23a which are resting on the side edges of the bags.

On the transverse beam 6 which carries the movable welding jaws is a holding component 31 having slots 32 in which feet 33 and 33a are mounted for adjustment transversely and to be able to rest against the bag 14 and the supporting component 17 when the beam 6 is lowered.

The device according to the invention operates in the following manner. When the newly made bag 14 is placed on the pile 30 of bags made during previous operations of the machine, and while the jaws 3a and 4a are in the raised position as shown in FIGS. 3 and 4, the side edges 34 of the bag 14 are located above the fingers 23 and 23a and the pile of bags 30 is pinched at its side edges between the fingers 23 and 23a and the supporting component 17.

The beam 6 is then lowered in the direction of the arrow A by rotation of the earns 11 and 11a so as to bring the upper welding jaws 3a and 4a into contact with the fixed lower jaws 3 and 4 for welding the tubing 2. Simultaneously, the holding component 31 firmly fixed to the beam 6 is lowered so that the feet 33 and 33a pinch the bag 14 and the pile of bags 30 against the supporting component 17 as shown in FIG. 5.

This holding of the bags by the component 32 and its feet 33 is maintained for the entire duration of the welding operation.

Thereafter, the cams 28 and 280 lift the rods 26 and 26a in order to raise the fingers 23 and 23a past the top bag in the direction of the arrow B, as shown in FIG. 6. The fingers are then located above the side edges 34 of the bag 14 as shown in FIG. 6. At this instant, the pile of bags is held down against the spring urged supporting component 17 only by the feet 33 and 33a of the holding component.

The fingers 23 then return to their original position following further rotation of the cams 28 and 28a to pinch simultaneously the side edges 34 of the bag 14 and the pile of bags 30 therebelow.

As soon as the welding and the cutting of the bag 14 have been completed, the beam 6 rises again in the opposite direction to the arrow A, so as to lift the upper jaws 3, 3a and the holding component 31, and to separate the feet 33 and 33a from the supporting component 17 as shown in FIG. 7.

The pile of bags 30 is then held by the fingers 23 and 23a again resting against the supporting component 17 and a new cycle can recommcnce for stacking the next hag.

According to another embodiment (not shown in the drawing), it is possible for the fingers 23 and 23a to be fixed in that the bar is firmly fixed to the frame 9 of the machine. In this case, the feet 33 and 33a of the holding component 31 pushthe supporting component 17 back during their descent in opposition to the spring 22 and they thus ensure that the pile of bags is held against the said supporting component, whilst disengaging the fingers 23 and 23a of the supporting component in order to make it possible for the side edges 34 of the bag 14 to be transferred to below the fingers 23 and 23a in a manner similar to that represented in FIG. 6.

Although a single pair of pinching fingers 23, 23a for one pile of bags has been shown, it is very obvious that it would be possible to stack several piles of bags and that, in this case, there would be as many pairs of fingers as there are stacks.

Of course, various modifications can be introduced by those skilled in the art to the devices or processes which have just been described purely by way of nonlimiting examples, without departing from the scope of the invention as defined by the following statement of claims. I

I claim:

1. In apparatus for forming stacks of bags from weldable film or tubing, comprising a frame, mobile welding jaw means movably mounted on said frame, furtherjaw means mounted on said frame in the path of movement of said movable jaw means and cooperating with said mobile jaw means, means for advancing film or tubing along a path extending between said movable jaw,

means and said further jaw means, means carried by said mobile jaw means for cutting said tubing or film transversely of the direction of movement thereof, drive means connected to said mobile jaw means for moving'said mobile jaw means toward and away from said further jaw means, supporting means downstream of said further jaw means for receiving and supporting said film or tubing and holding means connected to and operable by said drive means for movement toward and away from said supporting means for contacting one side of and holding said film or tubing against said supporting means during the welding of said film or tubing by said mobile jaw means, the combination therewith of at least one pair of pinching finger means, one finger means at one side of the path of movement of said film or tubing and the other finger means at the other side of said last-mentioned path and both said finger means extending in the direction transverse to the direction of advance of said film or tubing by an amount less than the dimension of said film or tubing in said transverse direction and normally being intermediate said path and said supporting means for contacting said film or tubing at the side thereof opposite from the side thereof engageable by said holding means prior to contact of said holding means with said film or tubing, one of said supporting means and said pair of finger means being movable toward and away from the other thereof to permit relative movement between said film or tubing and said finger means when said holding means contacts said film or tubing thereby to cause the latter and said pair of finger means to move relative to each other and to cause said pair of finger means to transfer its contact with said film or tubing to the side of said film or tubing contacted by said holding means.

2. Apparatus as set forth in claim 1, wherein said supporting means comprises a member mounted for movement in a plane perpendicular to the direction of advance of said film or tubing, and said holding means is mounted for movement with said mobile jaw means and in the plane of movement of said member.

3. Apparatus as set forth in claim 2, wherein said pinching finger means are mounted for movement in a plane parallel to the plane of movement of said member and are connected to said drive means for separating said pinching finger means from said supporting means when said holding means contacts said film or tubing.

4. Apparatus as set forth in claim 3, wherein said pinching finger means comprise a plurality of pairs of fingers, a transverse bar slidably carrying a pair of fingers, sliding rod means carrying said transverse bar, and cam drive means interconnecting said sliding rod means and said first-mentioned drive means for reciprocating said sliding rod means in the longitudinal direction thereof.

5. Apparatus as set forth in claim 2, wherein said member comprises a transverse bar and at least one rod slidably carried by said frame and carrying said transverse bar, and wherein resilient means are provided for urging said transverse bar against said pinching finger means.

and further comprising means acting between said member and said frame for resisting movement of said member away from said last-menti0ned path. 

1. In apparatus for forming stacks of bags from weldable film or tubing, comprising a frame, mobile welding jaw means movably mounted on said frame, further jaw means mounted on said frame in the path of movement of said movable jaw means and cooperating with said mobile jaw means, means for advancing film or tubing along a path extending between said movable jaw means and said further jaw means, means carried by said mobile jaw means for cutting said tubing or film transversely of the direction of movement thereof, drive means connected to said mobile jaw means for moving said mobile jaw means toward and away from said further jaw means, supporting means downstream of said further jaw means for receiving and supporting said film or tubing and holding means connected to and operable by said drive means for movement toward and away from said supporting means for contacting one side of and holding said film or tubing against said supporting means during the welding of said film or tubing by said mobile jaw means, the combination therewith of at least one pair of pinching finger means, one finger means at one side of the path of movement of said film or tubing and the other finger means at the other side of said last-mentioned path and both said finger means extending in the direction transverse to the direction of advance of said film or tubing by an amount less than the dimension of said film or tubing in said transverse direction and normally being intermediate said path and said supporting means for contacting said film or tubing at the side thereof opposite from the side thereof engageable by said holding means prior to contact of said holding means with said film or tubing, one of said supporting means and said pair of finger means being movable toward and away from the other thereof to permit relative movement between said film or tubing and said finger means when said holding means contacts said film or tubing thereby to cause the latter and said pair of finger means to move relative to each other and to cause said pair of finger means to transfer its contact with said film or tubing to the side of said film or tubing contacted by said holding means.
 2. Apparatus as set forth in claim 1, wherein said supporting means comprises a member mounted for movement in a plane perpendicular to the direction of advance of said film or tubing, and said holding means is mounted for movement with said mobile jaw means and in the plane of movement of said member.
 3. Apparatus as set forth in claim 2, wherein said pinching finger means are mounted for movement in a plane parallel to the plane of movement of said member and are connected to said drive means for separating said pinching finger means from said supporting means when said holding means contacts said film or tubing.
 4. Apparatus as set forth in claim 3, wherein said pinching finger means comprise a plurality of pairs of fingers, a transverse bar slidably carrying a pair of fingers, sliding rod means carrying said transverse bar, and cam drive means interconnecting said sliding rod means and said first-mentioned drive means for reciprocating said sliding rod means in the longitudinal direction thereof.
 5. Apparatus as set forth in claim 2, wherein said member comprises a transverse bar and at least one rod slidably carried by said frame and carrying said transverse bar, and wherein resilient means are provided for urging said transverse bar against said pinching finger means.
 6. Apparatus as set forth in claim 2, wherein said pinching finger means comprise fingers fixed in position relative to said frame and said holding means urges said member away from said path of said film or tubing, and further comprising means acting between said member and said frame for resisting movement of said member away from said last-mentioned path. 